As owner of many irobot roombas and scoobas, it's all fun and games till it enters the 'I think I'm stuck on something' state. I've watched mine try to unstick themselves from hang ups on furniture and rugs, and heaven forbid if it every got stuck up on a kitten there will be fur everywhere.
It revs up and floors it full ahead and reverse, back and forth, and those are some strong motors when they want to be. Add that to the spiky rubber tires and you have found a new way to skin a cat.